Search PubMed⌕ Search

Biomedical subjects

C D Fletcher

Publications and source records attributed to C D Fletcher.

At least 91 records · Page 5Linked to original sources
PubMed1998

Nerve sheath tumours with hybrid features of neurofibroma and schwannoma: a conceptual challenge.

AIMS: To characterize and delineate a subset of rare nerve sheath tumours showing hybrid features of neurofibroma and schwannoma. METHODS AND RESULTS: Nine lesions were identified in the authors' files showing predominant features of neurofibroma with distinct, often nodular regions of classical schwannomatous differentiation. Most patients were adults, eight out of nine were male. Of the nine lesions, two were dermal, two were subcutaneous and five were subfascial. Five lesions had a plexiform architecture and one patient had overt neurofibromatosis. One out of six patients with follow-up developed local recurrence. Schwannoma-like regions displayed strong S100 staining, in contrast to more varied and limited S100 reactivity in neurofibromatous areas. The Antoni A areas could be quite cellular with high MIB-1 proliferation indices. No lesion underwent malignant change. CONCLUSIONS: Our results demonstrate that some nerve sheath tumours may contain histologically clear components of both neurofibroma and schwannoma, suggesting that (despite evident and well-defined clinicopathological differences) these two lesions may be even more closely related than previously recognized. Whether this phenomenon results from a localized microenvironmental change or from a clonal genetic alteration remains unknown.

Adolescent↗
PubMed1998

Primary liposarcoma of the skin: a rare neoplasm with unusual high grade features.

Liposarcoma is the most common soft tissue sarcoma in adults. It presents in three main forms: well-differentiated liposarcoma (which includes adipocytic, sclerosing, inflammatory, spindle cell, and dedifferentiated subtypes), myxoid/round cell liposarcoma, and pleomorphic liposarcoma. Anatomic distribution depends largely on histologic subtype, but the deep soft tissue of the extremities and the retroperitoneum are most frequently affected. Whereas it is accepted that liposarcoma rarely occurs in the subcutaneous soft tissue, the dermis seems to represent an exceedingly rare site of occurrence. The clinicopathologic features of a series of seven primary cutaneous liposarcomas (two atypical lipomatous tumors/well-differentiated liposarcomas, one myxoid/round cell liposarcoma, and four pleomorphic liposarcomas) are analyzed here. Clinically, all of the patients were adults (four men, three women) with a median age of 72 years, and four of seven cases arose on the scalp. Local recurrences occurred in two patients, but no distant metastases or disease-related deaths have been observed. Although follow-up is relatively short, it appears that, exceptionally, liposarcoma occurs primarily in the skin and, despite an apparent tendency to show high-grade morphologic features, it seems to exhibit relatively indolent clinical behavior in this location.

Adipose Tissue↗
PubMed1998

Primary cutaneous Ewing's sarcoma: immunophenotypic and molecular cytogenetic evaluation of five cases.

Cutaneous small blue cell tumors are relatively uncommon and include primary lesions of either adnexal or neuroendocrine differentiation, as well as metastatic disease. Extraosseous Ewing's sarcoma/malignant primitive neuroectodermal tumor (MPNET) rarely may occur as a primary, superficially based neoplasm in children and young adults. We describe a series of five cases of Ewing's sarcoma/malignant primitive neuroectodermal tumor occurring as a primary cutaneous malignancy supported diagnostically both by immunohistochemical stains and fluorescence in situ hybridization (FISH). All five cases occurred as a solitary dermal nodule and were located in the lower extremities (3 cases), the axilla (1 case), and the flank (1 case). Three of the cases were clinically polypoid. Four of the five patients were female, and age at presentation ranged form 8 to 50 years of age (median, 18 years). All five tumors consisted of nodular proliferations of monomorphous, small blue cells with round, vesicular nuclei, and scant to moderate cytoplasm that were uniformly immunoreactive for the CD99 cell surface glycoprotein in a characteristic membranous pattern. Fluorescence in situ hybridization analysis of paraffin-embedded tissue revealed that three of four tumors were positive for a chromosomal translocation involving the EWS locus at 22q12, seen in more than 90% of cases of Ewing's sarcoma/malignant primitive neuroectodermal tumor. One case was not analyzable. All five patients were treated using local excision, and two patients additionally received postoperative chemotherapy and radiotherapy. Clinical follow-up is available in three cases (median duration, 33 months) and to date none has shown evidence of either local recurrence or metastasis. Because similar cases reported in the literature have likewise had favorable clinical courses after excision, primary cutaneous Ewing's sarcoma/malignant primitive neuroectodermal tumor may represent a clinically favorable subset of this otherwise highly aggressive neoplasm.

Adolescent↗
PubMed1998

Spindle cell rhabdomyosarcoma (so-called) in adults: report of two cases with emphasis on differential diagnosis.

Spindle cell rhabdomyosarcoma (RMS) is a recently described variant of embryonal RMS that carries a relatively favorable prognosis when compared with other forms of RMS. To date, spindle cell RMS has been described only in children. The authors have identified two unusual cases occurring in adults using the following criteria: tumors composed mainly of fascicular, relatively monomorphic spindle-shaped cells that show unequivocal immunohistochemical and ultrastructural evidence of myogenic differentiation. The tumors were identified in a 38-year-old woman and a 56-year-old man, arising in the cheek and left hemidiaphragm, respectively. Both were treated with surgical resection and chemotherapy. The first patient died of uncontrolled local recurrence of her tumor at 27 months after diagnosis, and the second died of metastatic disease at 13 months follow-up. The tumors were composed mainly of fascicles of spindle cells with palely eosinophilic cytoplasm admixed diffusely with sparse polygonal, rounded, or strap-shaped rhabdomyoblasts with brightly eosinophilic cytoplasm and with cross-striations in the first case only. Immunostaining for muscle-related antigens showed staining for smooth-muscle actin (focal), pan-actin HHF-35, desmin, fast myosin, myoglobin, and MyoD1. Both cases were negative for S-100 protein. On electron microscopy, both cases showed neoplastic rhabdomyoblasts with clear-cut sarcomeric differentiation in many of the tumor cells. Spindle cell RMS poses special problems in differential diagnosis when arising in adults and should be distinguished from leiomyosarcoma, malignant peripheral nerve sheath tumor with heterologous rhabdomyoblastic differentiation (malignant Triton tumor), and fibrosarcoma. In view of the good prognosis afforded children with spindle cell RMS and in light of the chemoresponsive behavior of RMS in general, we feel that it is important to identify tumors that meet the criteria for spindle cell RMS occurring in the adult population. However, based on these two cases, it is possible that spindle cell RMS occurring in adults may not be associated with such a favorable outcome.

Actins↗
PubMed1998

Myofibromatosis in adults, glomangiopericytoma, and myopericytoma: a spectrum of tumors showing perivascular myoid differentiation.

The clinicopathologic features of 24 tumors showing perivascular myoid differentiation are described. These included tumors with histologic features of "infantile-type" myofibromatosis occurring in adult patients (8 cases), tumors with composite features of "hemangiopericytoma" and glomus tumor (9 cases), and tumors with a distinctive concentric perivascular proliferation of spindle cells (7 cases). Evidence of morphologic overlap among these groups suggests they are closely related neoplasms that form a single spectrum. Age of patients with lesions resembling infantile-type myofibromatosis ranged from 23 to 67 years (median, 37 years). Clinicopathologic manifestations of this disease included multicentricity (4 cases), local recurrence (3 cases), persistence of congenital lesions into adulthood (4 cases), and tumors that were multifocal within the confines of one anatomic region (7 cases). Histologically, all cases showed a biphasic pattern that consisted of fascicles of spindle cells with abundant eosinophilic cytoplasm that resembled smooth muscle, in addition to a population of more primitive spindled cells associated with a hemangiopericytomalike vascular pattern. Six cases showed reversal of the typical zonation seen in pediatric cases in that the primitive component surrounded the more mature fascicular areas. Also described are nine tumors with features that are intermediate between glomus tumor and hemangiopericytoma, which we have designated glomangiopericytoma. These tumors are characterized by prominent branching vessels lined by a single row of endothelial cells surrounded by epithelioid cells with a glomoid appearance. In other areas, the tumors showed typical hemangiopericytomatous foci similar to those in the myofibromatosis cases. The principal points of distinction were a lack of myoid nodules and an absence of small primitive cells with basophilic cytoplasm. Ages of these patients ranged from 17 to 78 years (median, 35 years). All tumors were located in the subcutaneous tissue and the superficial soft tissue of the extremities. Recurrence developed in one of six patients with follow-up information. The recurrent tumor had features of angiomatoid malignant fibrous histiocytoma. Finally, we describe a subset of tumors characterized by concentric periluminal proliferation of bland, round to ovoid cells, which we have designated as myopericytoma. Patient age ranged from 10 to 66 years (median, 40 years). All were located in subcutaneous and superficial soft tissue of distal extremities. One patient had two recurrences in 3 years after initial excision. Our study suggests that these three lesional groups comprise a histologic continuum of tumors that share clinical similarities and that, perhaps, are designated more appropriately as perivascular myomas. The relationship of this family of tumors to so-called hemangiopericytoma is discussed.

Actins↗
PubMed1998

Fibrosarcomatous ("high-grade") dermatofibrosarcoma protuberans: clinicopathologic and immunohistochemical study of a series of 41 cases with emphasis on prognostic significance.

The fibrosarcomatous variant of dermatofibrosarcoma protuberans (FS-DFSP) represents an uncommon form of DFSP, in which the prognostic influence of the fibrosarcomatous component is still debated. We analyzed the clinicopathologic and immunohistochemical features in a series of 41 patients. Patient age ranged from 8 to 87 years (median, 48 years), and 19 patients were female. Twenty five lesions were seen on the trunk, 6 on the upper limbs, and 4 on the lower limbs, and five neoplasms were located in the head/neck region; in one case, exact anatomic site was unknown. Twenty seven tumors involved purely dermal and subcutaneous tissues, in 10 cases, deeper structures were also involved, 1 case arose in the breast, and, in 3 cases, it was impossible to define exact depth of the lesion. Preoperative duration ranged from 1 month to 60 years (median, 3 years). Twenty six tumors were excised locally with clear margins, 7 were treated by wide excision, 3 by incomplete excision, and, in 4 patients, the lesion was shelled out. In one case, exact treatment was unknown. In addition, radiotherapy was administered in three cases and chemotherapy in one case. Histologically, the lesions showed areas of typical, low-grade DFSP adjacent to fibrosarcomatous areas. In four cases, a previously ordinary DFSP recurred as pure fibrosarcoma, in two cases, local recurrence of FS-DFSP showed features of ordinary DFSP. Fibrosarcomatous change was more common in the primary (de novo) lesions than in recurrent lesions (3.6:1). Proportion of fibrosarcoma varied between < 30% in 6 cases to > 70% of tumor tissue in 21 cases. An abrupt transition between both components was seen in 19 cases. The fibrosarcomatous component showed focal necrosis in seven cases and showed a higher mitotic rate in comparison with ordinary DFSP areas (mean, 13.4 versus 2.3 mitoses in 10 high-power fields). Additional histologic features included progression to pleomorphic sarcoma in 2 recurrent cases, melanin-pigmented cells (Bednar FS-DFSP) in 1 case, focal myxoid change in 13 cases, plaque or keloidlike hyalinization in 3 cases, and myoid bundles and nodules in 9 cases. Immunohistochemically, tumor cells in DFSP areas stained positively for CD34, whereas, in FS-DFSP areas, only 15 out 33 cases were positive for CD34. Follow-up in 34 of 41 patients (mean, 90 months; median, 36 months) revealed local recurrence in 20 patients (58%) (recurrence occurred in 5 patients on two or more occasions). Metastases (5 lung, 1 bone, and 1 soft tissue) were seen in 5 patients (14.7%), and 2 patients have died of tumor to date (5.8%). Necrosis, high mitotic rate (> 10 mitoses per 10 high-power fields), and presence of pleomorphic areas in FS-DFSP tended to be related with poor clinical outcome, but no statistically significant association was detected. Fibrosarcomatous change in DFSP represents a form of tumor progression in DFSP and is associated with a significantly more aggressive clinical course than in ordinary DFSP, indicating a possible need for treatment intensification in such cases.

Actins↗
PubMed1998

Angiosarcoma of the ovary: clinicopathologic and immunohistochemical analysis of four cases with a broad morphologic spectrum.

Angiosarcoma most frequently occurs in the skin of the head and neck region of elderly persons, lymphedematous limbs, or in deep soft tissue but only rarely has been described to occur in the female genital tract. Four cases of angiosarcoma of the ovary are described herein. They occurred in patients 25 to 42 years old (median, 31 years). The most common clinical presentation was abdominal pain. All of the tumors were unilateral, hemorrhagic, and ranged from 3.5 cm to 14 cm (median, 13 cm). The histologic appearance of the tumors was varied, and often the vascular nature of the tumor was not apparent immediately. Some of the tumors had a fascicular growth pattern composed of spindle-shaped cells with ovoid nuclei and ample eosinophilic cytoplasm closely mimicking leiomyosarcoma. Other tumors resembled ovarian yolk sac tumor with a reticular growth pattern, whereas, in other areas, cystic structures lined by hobnailed hyperchromatic enlarged nuclei simulated clear cell carcinoma of the ovary. Despite these misleading morphologic findings, all cases were characterized, at least focally, by vasoformative channels or discrete cytoplasmic vacuoles, and all were immunoreactive for vascular markers. Two patients with spread of tumor outside of the ovary died 1 month and 2 years after initial diagnosis, respectively. Two patients with tumor confined to the ovary are alive without evidence of disease 3 and 14 months after diagnosis, respectively. The differential diagnosis of this unusual neoplasm is discussed, and the literature is reviewed.

Adult↗
PubMed1998

Dedifferentiated liposarcoma: a report of nine cases with a peculiar neurallike whorling pattern associated with metaplastic bone formation.

Nine cases of dedifferentiated liposarcoma with both a peculiar neurallike or meningeallike whorling pattern and metaplastic bone formation are reported. The tumors predominated in the retroperitoneum of elderly adults. All nine tumors were resected, and five of seven that were followed-up recurred locally, but none metastasized after a follow-up of 2 to 7 years. Grossly, most of the tumors were huge masses, ranging from 2.5 cm to 60 cm. Histologically, the tumors revealed, in addition to areas of well-differentiated liposarcoma, discrete nodules consisting of hypercellular, spindled to ovoid cellular proliferation arranged in tight, concentric whorls resembling neural tumors or meningiomas. Metaplastic, heterotopic ossification was present in seven of nine tumors and consisted of variable amounts of osteoblast-rimmed bone trabeculae situated at the periphery of the whorled areas or intimately mixed with the whorled cellular component. Immunohistochemical studies were inconclusive in determining the nature of the dedifferentiated, whorled element. Ultrastructural evaluation of one tumor disclosed neoplastic cells featuring thin, interdigitating cytoplasmic processes connected by desmosomes, similar to those described in follicular dendritic cell neoplasms. Although suggested by the light and electron microscopic features, the follicular dendritic cell differentiation of the dedifferentiated component could not be confirmed on immunohistochemical grounds, and the histogenesis of the intriguing neurallike or meningiomalike component in these dedifferentiated liposarcomas is unknown.

Adult↗
PubMed1998

Atypical or worrisome features in cellular neurothekeoma: a study of 10 cases.

Cellular neurothekeoma is a recently characterized benign cutaneous neoplasm arising usually on the upper trunk or head and neck of children or young adults. Typical histology is that of a lobulated dermal tumor composed of spindle and epithelioid cells, arranged in fascicles and nests, lacking immunoreactivity for S-100 protein, but usually being NK1/C3 positive. We present 10 new cases of cellular neurothekeoma with atypical histologic features that have not been described previously and that suggested the possibility of malignancy. The age range of affected patients was 1 to 44 years (median, 20.5 years); sites included the head and neck (three cases), the upper limbs (two cases), the lower limbs (two cases), and the trunk (two cases). Atypical findings in individual cases included large size (up to 6 cm), deep penetration (extending into skeletal muscle or subcutaneous fat, or both), diffusely infiltrative borders, vascular invasion, high mitotic rate, and marked cytologic pleomorphism. Clinical follow-up was available in 7 of 10 cases. Although the atypical features raised concern about the biologic potential of these lesions, preliminary follow-up (1-5 years) has shown no recurrence and suggests that complete surgical excision of these lesions is curative. These new data expand the morphologic spectrum of cellular neurothekeoma.

Adolescent↗
PubMed1998

Low-grade myofibroblastic sarcoma: analysis of 18 cases in the spectrum of myofibroblastic tumors.

The clinicopathologic, immunohistochemical, and ultrastructural features of a seemingly distinctive low-grade spindle cell sarcoma showing myofibroblastic differentiation have been analyzed in a series of 18 patients. The age range of the patients (7 women and 11 men) was 19-72 years (median: 42 years). A painless, enlarging mass was the most common clinical presentation. Five tumors arose in the oral cavity (including four lesions in the tongue), four in the lower extremities and three in the upper extremities, four cases in the abdominal/pelvic cavity, and two on the trunk. Eight soft-tissue cases involved skeletal muscle, three cases were located in perifascial tissues, and two arose in subcutaneous tissue. Tumor size ranged from 1.4 to 17 cm (median: 4 cm); in six cases (of which four were abdominal/pelvic) the lesion was larger than 5 cm. All patients were treated surgically, and four received additional adjunctive therapy. Histologically, most cases were cellular lesions showing a diffusely infiltrative pattern, and were composed of spindle-shaped tumor cells arranged mainly in fascicles. Tumor cells had poorly defined, palely eosinophilic cytoplasm and fusiform nuclei, which were either tapering and wavy or plumper and vesicular with indentations and small inconspicuous nucleoli. Tumor cells were set in a collagenous matrix often with prominent hyalinization. Mild nuclear atypia was noted in 16 cases; in the other 2 cases, and in the metastases of one other lesion, a greater degree of nuclear atypia was seen. In all but one case, the mitotic rate ranged from 1 to 6 mitoses in 10 HPFs (mean: 2/10 HPFs); in a single case, there were more than 20 mitoses in 10 HPFs. Immunohistochemically, all cases stained positively for at least one myogenic marker; 12 cases were positive for desmin, 11 for alpha-smooth muscle actin, and 6 for muscle actin (HHF35). Seven neoplasms were desmin positive/ alpha-smooth-muscle actin negative, and five cases were desmin negative/alpha-smooth-muscle actin positive emphasizing the variable immunophenotype of myofibroblastic lesions. In addition, 7 of 10 tumors stained at least focally positive for fibronectin. Ultrastructural examination in five cases showed characteristic features of myofibroblasts. Follow-up in 11 patients (median: 29 months) revealed local recurrence in 2 cases, and multiple distant soft-tissue, intraosseous, and pulmonary metastases in one other patient. Low-grade myofibroblastic sarcoma seems to represent a distinct entity in the spectrum of low-grade myofibroblastic neoplasms and is distinguishable from fibromatosis, myofibromatosis, solitary fibrous tumor, fibrosarcoma, and leiomyosarcoma.

Actins↗
PubMed1998

Atypical and malignant solitary fibrous tumors in extrathoracic locations: evidence of their comparability to intra-thoracic tumors.

Solitary fibrous tumor (SFT), first described as a pleural lesion, has been reported at numerous extrathoracic sites over the past 10 years. About 10% to 15% of intrathoracic SFTs are histologically or clinically malignant, but such cases have very rarely been described at other locations. Among 92 cases of extrathoracic SFT in our files, we identified 10 that either had recurred (2 cases) or had a least one atypical histologic feature (8 cases). The ten tumors occurred in five men and five women, 32 to 81 years old (median 56), measured 1.9 cm to 20 cm (median 11.5 cm), and were located in the abdomen/pelvis (4 cases), retroperitoneum (3 cases), groin, trunk, and upper arm. Nuclear atypia (8 cases), markedly increased cellularity (6 cases), areas of necrosis (4 cases), and greater than 4 mitoses/10 HPFs (3 cases) were seen in addition to the typical histologic features of SFT. Six tumors had at least two of these atypical histologic features. Nine cases were positive for CD34, six were positive for O-13, and one was focally positive for smooth muscle actin. Eight were excised completely. Subsequent follow-up revealed tumor relapse in eight cases (follow up 6-180 months, median 24). Four patients had local recurrence at 12 to 168 months. Distant metastasis developed at 1 to 6 years in five cases with spread to lung (2 cases), liver (4 cases), and bone. Metastasis or local recurrence developed within 2 years in five patients. To date, no patient has died of their tumor. These findings demonstrate that nuclear atypia, hypercellularity, greater than 4 mitoses/10 HPFs, and necrosis may be seen in up to 10% of extrathoracic SFTs, and are associated with, but are not by themselves predictive of, aggressive clinical behavior. In addition, our findings confirm that the behavior of extrathoracic SFTs is unpredictable, entirely comparable to that of their better known pleural counterparts, and confirm that patients with SFTs in all locations require careful, long-term follow up. It is probably unwise to regard any such lesion as definitely benign.

12E7 Antigen↗
PubMed1998

Liposarcoma (atypical lipomatous tumors) of the vulva: a clinicopathologic study of six cases.

Liposarcoma, the most common soft tissue sarcoma, usually arises in the limbs, trunk, or abdomen, but very rarely in the vulva. Six cases of liposarcoma of the vulva are described here. They were characterized by their occurrence in predominantly middle-aged women (median age 52), variable size, and focally infiltrative margin. The preoperative clinical diagnosis for all patients was of a benign lesion, with a diagnosis of lipoma in two. Four of six cases had the usual histologic appearance of a well-differentiated liposarcoma/atypical lipomatous tumor with variation in adipocyte size, adipocytic nuclear atypia, and occasional lipoblasts. Two of the six cases had a very unusual histologic appearance, not previously described, with an admixture of neoplastic bland spindle and round cells along with adipocytes showing variation in size as well as numerous mainly bivacuolated lipoblasts. Liposarcomas of other types were not identified. Follow-up data were available for five of the six patients and all were treated by excision with no additional treatment. Four showed no sign of recurrence at 12, 14, 18, and 84 months. One tumor was incompletely excised, regrew over a 10-year period, was re-excised, and showed no further recurrence 31 months thereafter. Liposarcoma can occur in the vulva, is predominantly of the well-differentiated subtype, can show an unusual histologic appearance with an admixture of spindle cells and numerous lipoblasts, and seems to have a behavior similar to these tumors in other anatomic locations.

Adult↗
PubMed1998

Evaluation of fluorodeoxyglucose positron emission tomography in the management of soft-tissue sarcomas.

We performed a retrospective analysis to evaluate the ability of whole-body F-fluorodeoxyglucose positron emission tomography (FDG PET) to identify local recurrence and pulmonary metastases in patients with soft-tissue tumours after treatment. We compared the results of FDG PET with those of MRI for the detection of local recurrence, and with CT of the chest for pulmonary metastases. We assessed 62 patients of mean age 51 years, who had 15 types of soft-tissue sarcoma, after a mean follow-up of 3 years 2 months. For the detection of local disease, 71 comparisons showed that the sensitivity and specificity of FDG PET were 73.7% and 94.3%, respectively; there were 14 true-positive and five false-negative results. MRI had a sensitivity and specificity of 88.2% and 96.0% respectively. For the identification of lung metastases, 70 comparisons showed that the sensitivity and specificity of FDG PET were 86.7% and 100%, with 13 true-positive results and two false-negative results. CT of the chest had a sensitivity and specificity of 100% and 96.4%. Thirteen other sites of metastases were identified by FDG PET. FDG PET can identify both local and distant recurrence of tumour as a one-step procedure and will detect other metastases. It seems that all three methods of imaging are needed to define accurately the extent of disease, both at initial staging and during follow-up.

Adolescent↗
PubMed1998

Recent developments in soft tissue tumors.

The field of soft tissue tumor pathology, despite the relative rarity of the lesions concerned, has grown considerably in recent years and has featured very prominently in the academic pathology literature. This stems from the facts that increasing diagnostic sophistication has allowed the continued refinement of classification schemes and the delineation of numerous previously unrecognized 'entities' and that the application of modern cytogenetic and molecular genetic techniques has revealed the remarkable importance of reproducible cytogenetic aberrations in our understanding of the pathobiology of this group of neoplasms. This presentation will aim to summarize data regarding some of the recently characterized entities as well as the major molecular genetic advances. Newly characterized 'entities' which are important because of the ease with which they are confused with lesions of very different biologic potential include chondroid lipoma, pleomorphic hyalinising angiectatic tumor, extrapleural solitary fibrous tumor, giant cell angiofibroma, cellular angiofibroma, retiform hemangioendothelioma, composite hemangioendothelioma and low grade fibromyxoid sarcoma. The 'hemangioendotheliomas' also represent an important area of conceptual evolution as we begin to more critically analyze the concept of borderline malignancy. Concerning molecular genetic advances, the most striking data to emerge are the frequency of tumour-specific reciprocal translocations, the frequency of biologically revealing cytogenetic aberrations in benign lesions and the emerging evidence of striking differences in cell cycle abnormalities in the different sarcoma types.

Angiofibroma↗
PubMed1998

Myofibroblastic tumours: an update.

The concept of the myofibroblast is relatively new, since this cell type was defined less than 30 years ago, and there is as yet no firm consensus as to how a myofibroblast should be defined either morphologically or phenotypically. Because its attributes place it midway between a fibroblast and a smooth muscle cell and because it appears capable of functional and phenotypic modulation, some authorities argue that there is no such thing as a truly myofibroblastic tumour. However, since most diagnostic tumour pathology is based on phenotypic features of the excised lesion, it is an unavoidable fact that a wide range of soft tissue tumours show convincing myofibroblastic features. Lesions in this category fall into four main groups--the family of reactive fasciitis-like lesions, a group of benign lesions most of which have been fairly recently recognized (e.g., mammary myofibrolastoma, intranodal myofibroblastoma, angiomyo-fibroblastoma and dermatomyofibroma), the locally aggressive fibromatoses (either superficial or deep) which share features of fibroblasts and myofibroblasts in varying degree and, finally, sarcomas showing myofibroblastic differentiation. These latter include low grade lesions such as so-called infantile fibrosarcoma, inflammatory myofibroblastic tumour and a distinctive form of low grade myofibroblastic sarcoma, as well as some of the high grade lesions formerly known as MFH. Based on the advances made in the past 20 years, it makes no sense to deny the existence of myofibroblastic tumours (especially in an era when histogenetic concepts have crumbled)--instead we need to work towards a reproducible and agreed definition of the myofibroblast.

Child↗
PubMed1998

Tenosynovial giant cell tumors: evidence for a desmin-positive dendritic cell subpopulation.

Diffuse tenosynovial giant cell tumor (DGCT) could present as a large intra-articular mass (pigmented villonodular synovitis, or PVNS) or as an extraarticular mass, which might be confused with a sarcoma, particularly when growth is destructive and giant cells are few. Prompted by a DGCT in which a subpopulation of cells was desmin positive and in which an erroneous diagnosis of myosarcoma was made, we analyzed the frequency of desmin, myogenin, MyoD1, and muscle-specific actin immunoreactivity in 45 well-characterized GCTs. We also analyzed a subset of these cases with antibodies to smooth muscle actin, as well as macrophage, follicular dendritic cell, extrafollicular dendritic cell, and dermal dendrocyte-associated antigens. Sections from 45 cases of formalin-fixed GCTs (22 DGCTs, 13 cases of PVNS, and 10 localized GCTs) were immunostained for desmin, myogenin, MyoD1, and muscle-specific actin. The eight cases that showed the largest number of desmin-positive cells were immunostained for smooth muscle actin, CD45, CD68, CD21, CD35, cytokeratin 8, and Factor XIIIa. Desmin-positive cells were seen in 20 (43%) of 45 cases: 10 (43%) of 22 DGCTs, 5 (38%) of 13 cases of PVNS, and 5 (50%) of 10 localized GCTs. In contrast, none were positive for any of the other muscle-associated proteins. In almost all of the cases, the desmin-positive cells were large and dendriform, with long processes that interdigitated between adjacent round cells. Desmin immunoreactivity was found in almost 50% of all GCTs, in the absence of positivity for other muscle markers. Desmin immunoreactivity in GCT seemed to be confined to a variably sized subpopulation of large dendritic cells whose exact identity remains uncertain.

Actins↗
PubMed1997

Myxoid chondrosarcoma (chordoid sarcoma) of bone: a report of two cases and review of the literature.

BACKGROUND: Chondrosarcoma of bone is a well recognized, relatively common clinicopathologic entity. Morphologically distinct soft tissue chordoid sarcoma (CS), or extraskeletal myxoid chondrosarcoma, is a relatively rare tumor that has generally been documented in extraosseous soft tissues. METHODS: The clinical and pathologic features of two patients with biopsy-proven CS from the pathology files of the Mayo Clinic and St. Thomas's Hospital were evaluated. Routine hematoxylin and eosin-stained slides were reviewed in both cases. Sections from both were examined immunohistochemically using the avidin-biotin-peroxidase technique and employing commercially available antibodies to the following antigens: S-100 protein, cytokeratin (AE1/AE3), epithelial membrane antigen (EMA), CD31, and factor VIII. Appropriate positive and negative controls were utilized throughout these procedures. Cytogenetic analysis was performed on fresh samples obtained from one tumor. Clinical data were obtained from the patients' medical records. RESULTS: The two cases of primary CS of bone arose from the right distal femur and right scapula, respectively, in 2 men ages 48 and 76 years, respectively. Morphologically, the tumors were lobulated, multinodular, and comprised of a uniform population of rounded to slightly spindled cells. Nuclei were hyperchromatic with inconspicuous nucleoli and surrounded by clear, vacuolated to eosinophilic cytoplasm. Neoplastic cells were arranged in anastomosing chords, strands, and, less often, nests and pseudopapillary structures embedded in an abundant, mostly hypovascular, mucinous matrix. Foci of hemorrhage and cystic degeneration were present in both tumors. No well developed hyaline cartilage or neoplastic osteoid was observed. Immunohistochemically, one neoplasm showed focal positivity for S-100 protein but was uniformly negative for cytokeratin (AE1/AE3), factor VIII, and CD31. The other tumor showed no immunopositivity with cytokeratin, EMA, or S-100 protein. Cytogenetic analysis in the latter tumor revealed a nonrandom reciprocal chromosomal translocation, t(9;22)(q22-31;q11-12). Both patients developed local recurrences and widespread distant metastases. Wide surgical excision was the primary mode of therapy. One patient died of tumor. CONCLUSIONS: Skeletal CS is an extraordinarily rare neoplasm with a distinct morphology. Although follow-up data were limited to only four examples, including two from the literature, the clinical course appears worse than that for usual chondrosarcoma of bone. Wide surgical resection appears to represent the best mode of therapy. The role of chemotherapy and radiation therapy has not been clearly defined.

Aged↗